Liu Zhao-Hui, Chen Jing-Zao, Ye Lin, Liu Jing, Qiu Jian-Yong, Xu Jian, Lu Rui, Yuan Xiao-Chao, Zhang Wen-Dong, Li Xiao-Fang, Li Gong
Department of Physiotherapy and Rehabilitation, Tangdu Hospital, Fourth Military Medical University, Xi'an 710038, P.R. China.
Mol Med Rep. 2010 Nov-Dec;3(6):917-21. doi: 10.3892/mmr.2010.369. Epub 2010 Sep 22.
In the present study, we investigated the effect of infrasound on the expression of N-methyl-D-aspartate (NMDAR)1 as well as changes in intracellular calcium ion concentration ([Ca2+]i) in the hippocampus of rats. Sprague-Dawley (SD) rats were exposed for 2 h daily to infrasound at 8 Hz 90 dB or 130 dB, and NMDAR1 expression was examined on days 1, 7, 14, 21 and 28. The expression of NMDAR1 in the rat hippocampus upon exposure to infrasound at 8 Hz 90 dB sound pressure level (SPL) showed an initial decrease on day 1, an increase on days 7 and 14, a further decrease on day 21, and a return to normal levels on day 28. The peak level was observed on day 14 in every examined subregion of the hippocampus. By contrast, exposure to infrasound at 8 Hz 130 dB SPL had opposite effects, showing an increase on day 1, a decrease on day 7, a decrease to the lowest point on days 14, another increase on day 21 and a return to normal levels on day 28. The lowest expression of NMDAR1 was found in the CA1 and CA3 regions on day 14 and in the DG region on day 7 with exposure at 130 dB. There were significant differences in [Ca2+]i concentration on days 14 and 21 with infrasonic exposure at both 8 Hz 90 dB and 130 dB, but no significant differences in [Ca2+]i concentration on days 1, 7 and 28 compared to the control group. The highest [Ca2+]i level was noted on day 14 with infrasound exposure at 8 Hz 130 dB. These changes suggest that 8 Hz 90 dB/130 dB infrasound exposure induced certain reversible changes in NMDAR1 expression and [Ca2+]i concentration in hippocampal cells, which may influence mnemonic functions related to the hippocampus.
在本研究中，我们调查了次声对大鼠海马中N-甲基-D-天冬氨酸受体（NMDAR）1表达以及细胞内钙离子浓度（[Ca2+]i）变化的影响。将Sprague-Dawley（SD）大鼠每天暴露于8Hz、90dB或130dB的次声中2小时，并在第1、7、14、21和28天检测NMDAR1的表达。在8Hz、90dB声压级（SPL）的次声暴露下，大鼠海马中NMDAR1的表达在第1天最初下降，在第7天和第14天增加，在第21天进一步下降，并在第28天恢复到正常水平。在海马的每个检测亚区中，第14天观察到峰值水平。相比之下，暴露于8Hz、130dB SPL的次声具有相反的作用，在第1天增加，在第7天减少，在第14天降至最低点，在第21天再次增加，并在第28天恢复到正常水平。在130dB暴露下，第14天在CA1和CA3区域以及第7天在齿状回（DG）区域发现NMDAR1的最低表达。在8Hz、90dB和130dB次声暴露下，第14天和第21天[Ca2+]i浓度存在显著差异，但与对照组相比，第1、7和28天[Ca2+]i浓度无显著差异。在8Hz、130dB次声暴露下，第14天观察到最高的[Ca2+]i水平。这些变化表明，8Hz、90dB/130dB次声暴露诱导了海马细胞中NMDAR1表达和[Ca2+]i浓度的某些可逆变化，这可能会影响与海马相关的记忆功能。
